Gradient copolymer, composition including same and cosmetic make-up or care method

ABSTRACT

Novel gradient copolymers including at least two different and specifically selected monomers, and cosmetic or skin-care compositions including same. The invention also relates to a cosmetic method for make-up or the care of keratin materials, in particular the skin of the body or of the face, the nails, the hair and/or the eyelashes, comprising the application of a cosmetic composition as defined above on said materials.

The present invention relates to novel topical cosmetic ordermatological compositions comprising specific gradient copolymerswhich are preferably soluble in the solvent medium of the composition,which can comprise cosmetic oils and/or solvents; the invention alsorelates to the specific copolymers.

In the field of cosmetics, there is often a search to have availablecompositions which make it possible to obtain a deposited layer, inparticular an adhesive or film-forming deposited layer, on thekeratinous substances under consideration, such as the hair, skin,eyelashes or nails.

In particular, these compositions can contribute color (make-up or hairdyeing compositions), gloss or matteness (compositions for caring for ormaking up the skin), physical properties, such as shaping (haircompositions, in particular styling compositions) or care or protectionproperties (care compositions, for example moisturizing or UV protectioncompositions). Good persistence and hold over time of the depositedcosmetic layer and good adhesion to the support are generally soughtfor. In particular, it is desirable for this deposited layer to be ableto withstand mechanical attacks, such as rubbing actions or transfers bycontact with another object, and to withstand water, sweat, tears, rain,sebum and oils. This is particularly true in makeup, in particular inthe field of lipsticks, where prolonged hold of the color and of thegloss and the nontransfer of the color are sought for; in the field offoundations, eyeshadows and powders, where the hold of the colorintroduced, while maintaining the matteness of the initial makeup for aslong as possible despite the secretion of sebum and sweat, and thenontransfer are sought for. In addition, the makeup compositions shouldbe comfortable to wear and should not exhibit an excessively tackytexture.

It is possible, in order to achieve all these often conflictingproperties in the same composition, to employ a blend of severalpolymers of very different chemical natures, each polymer contributingone of the desired characteristics. However, the use of a blend ofpolymers having different and not necessarily compatible chemicalnatures can cause problems of phase separation in the composition.

The use of random polymers, for example of conventional acrylic polymersobtained by conventional radical polymerization with a random mixture ofmonomers, does not make it possible to satisfactorily solve theseproblems. This is because the random polymers known in the prior artexhibit a dispersity in composition of the polymer chains, which alsoresults in phase separation of the polymers in the formulation.

The aim of the present invention is to overcome the disadvantages of theprior art by providing a cosmetic or dermatological compositioncomprising specific polymers which prevent the problems of phaseseparation in the formulation while making it possible to contribute thedesired cosmetic properties.

A subject matter of the present invention is thus a gradient copolymercomprising at least two different monomers both chosen from isobornylacrylate, isobornyl methacrylate, isobutyl acrylate, isobutylmethacrylate and 2-ethylhexyl acrylate.

Another subject matter of the invention is a cosmetic or dermatologicalcomposition comprising said copolymer.

Advantageously, the copolymers according to the invention are completelysoluble in the solvent medium of the composition, which can comprisecosmetic oils and/or solvents.

As the gradient copolymers according to the invention exhibit a lowdispersity in composition, all the chains exhibiting virtually the samestructures, they are therefore compatible with one another; the resultof this is that the cosmetic compositions comprising these copolymers donot exhibit the disadvantages and limitations of the compositions of theprior art.

In particular, the copolymers according to the invention exhibit theadvantage of being able to be easily employed in organic cosmetic media,in particular of oil or lipophilic solvent type, while retainingadvantageous rheological properties.

The copolymers according to the invention are gradient copolymers whichcomprise at least two different monomers chosen from a given list andwhich preferably exhibit a low polydispersity in weight and preferably alow polydispersity in composition.

The polydispersity in weight can be illustrated using the weightpolydispersity index (PI) of the copolymer, which is equal to the ratioof the weight-average molecular weight (Mw) to the number-averagemolecular weight (Mn). A low dispersity in mass reflects approximatelyidentical chain lengths, which is the case for the copolymers accordingto the present invention.

Preferably, the gradient copolymer according to the invention has aweight polydispersity index of less than or equal to 3, preferably ofbetween 1.1 and 2.5, in particular between 1.15 and 2.3, indeed evenbetween 1.2 and 2.0, or 1.9 or even 1.8.

Furthermore, the weight-average molecular weight of the gradientcopolymer is preferably between 2000 g/mol and 1 000 000 g/mol, inparticular between 3000 g/mol and 800 000 g/mol and better still between5000 g/mol and 500 000 g/mol.

Preferably, the number-average molecular weight of the gradientcopolymer is between 2000 g/mol and 1 000 000 g/mol, in particularbetween 3000 g/mol and 800 000 g/mol and better still between 5000 g/moland 500 000 g/mol.

The weight-average molecular weights (Mw) and the number-averagemolecular weights (Mn) are determined by gel permeation liquidchromatography (GPC), eluent THF, calibration curve established withlinear polystyrene standards, refractometer detector.

The gradient copolymer according to the invention also preferablyexhibits a low dispersity in composition. This means that all the chainsof copolymers have a composition (that is to say, a sequence ofmonomers) which is approximately the same and are therefore homogeneousin composition. In order to show that all the chains of copolymers havea similar composition, use will advantageously be made of liquidadsorption chromatography (or LAC), which makes it possible to separatethe chains of copolymers not according to their molecular weight butaccording to their polarity. The latter reflects the chemicalcomposition of the polymers constituting the material, the monomersbeing known. Reference may be made to the publication Macromolecules(2001), 34, 2667, which describes the LAC technique.

The polydispersity in composition can be defined in particular from theadsorption chromatography (LAC) curve (curve representing the proportionof polymers as a function of the elution volume): if “V^(1/2) min” isused to denote the minimum value of the elution volume at mid-height ofthe curve and if “V^(1/2) max” is used to denote the maximum value ofthe elution volume at mid-height of the curve, the polydispersity incomposition is generally regarded as low if the difference (V^(1/2)max−V^(1/2) min) is less than or equal to 3.5, in particular between 1and 2.8 and better still between 1.2 and 2.5.

Furthermore, the LAC curve can be defined by a Gaussian curve offormula:

$y = {{\frac{A}{w\sqrt{\frac{\pi}{2}}} \times ^{{- 2}\frac{{({x - x_{0}})}^{2}}{w^{2}}}} + y_{o}}$

in which:

-   -   x₀ is the value of x (elution volume) at the center of the peak    -   w is equal to twice the standard deviation of the Gaussian        distribution (i.e. 2σ) or alternatively corresponds to        approximately 0.849 times the width of the peak at mid-height    -   A represents the area under the peak    -   y_(o) is the value of y corresponding to x₀.

The dispersity in composition of the copolymer according to theinvention can also be defined by the value w as defined above.Preferably, said value w is between 1 and 3, in particular between 1.1and 2.3 and even better still between 1.1 and 2.0.

The gradient copolymers according to the invention can be obtained byliving or pseudo-living polymerization. For the record, it should beremembered that living polymerization is a polymerization in which thegrowth of the polymer chains only stops when the monomer disappears. Thenumber-average molecular weight (Mn) increases with the conversion.Anionic polymerization is a typical example of living polymerization.Such polymerizations result in copolymers having a low dispersity inmass, that is to say in polymers with a weight polydispersity index (PI)generally of less than 2.

For its part, pseudo-living polymerization is associated with controlledradical polymerization. Mention may be made, among the main types ofcontrolled radical polymerization, of:

-   -   radical polymerization controlled by nitroxides. Reference may        in particular be made to patent applications WO 96/24620 and WO        00/71501, which disclose the tools of this polymerization and        their use, and to the papers published by Fischer (Chemical        Reviews, 2001, 101, 3581), by Tordo and Gnanou (J. Am. Chem.        Soc., 2000, 122, 5929) and by Hawker (J. Am. Chem. Soc., 1999,        121, 3904);    -   atom transfer radical polymerization, disclosed in particular in        application WO 96/30421 and which proceeds by the reversible        insertion over an organo-metallic complex in a bond of        carbon-halogen type;    -   radical polymerization controlled by sulfur derivatives of        xanthate, dithioester, trithiocarbonate or carbamate type, such        as disclosed in applications FR 2 821 620, WO 98/01478, WO        99/35177, WO 98/58974, WO 99/31144 and WO 97/01478 and in the        publication by Rizzardo et al. (Macromolecules, 1998, 31, 5559).        Controlled radical polymerization denotes polymerizations in        which the secondary reactions which usually result in the        disappearance of propagating entities (termination or transfer        reaction) are rendered highly improbable in comparison with the        propagation reaction by virtue of an agent for controlling the        free radicals. The disadvantage of this method of polymerization        lies in the fact that, when the concentrations of free radicals        become high in comparison with the concentration of monomer, the        secondary reactions again become determining and tend to broaden        the distribution of the weights.

By virtue of these polymerization methods, the polymer chains of thegradient copolymers according to the invention grow simultaneously andtherefore incorporate at each instant the same ratio of comonomers. Allthe chains therefore have the same structures or similar structures,resulting in a low dispersity in composition. These chains also have alow weight polydispersity index.

Gradient copolymers are copolymers exhibiting a change in the ratio ofthe various monomers all along the chain. The distribution in thepolymeric chains of the comonomers depends on the change during thesynthesis in the relative concentrations of the comonomers.

The copolymers according to the invention comprise at least twodifferent monomers, the concentration of which along the polymer chainchanges gradually and in a systematic and predictable way.

This means that all the polymer chains have at least one monomer Mi forwhich, whatever the normalized position x on the polymer chain, there isa nonzero probability of encountering this monomer Mi along the chain.

One of the characteristics which makes it possible to define gradientcopolymers is the fact that, at any instant in the polymerization, allthe chains are subjected to the presence of the combination of all themonomers. Thus, in the reaction medium, the concentration of eachmonomer is always nonzero at any instant in the polymerization.

This makes it possible to distinguish the copolymers according to theinvention from conventional block polymers in which the change in themonomers along the polymer chain is not systematic; for example, for anAB diblock, within the A block, the concentration of the other monomer Bis always zero.

In the case of random polymers, the change in the monomers along thepolymer chain will not be gradual, systematic and predictable either. Arandom polymer obtained by conventional radical polymerization of twomonomers is distinguished from a gradient copolymer by the distributionof the monomers, which is not identical over all the chains, and by thelength of said chains, which is not identical for all the chains.

For a theoretical description of gradient copolymers, reference may bemade to the following publications:

-   T. Pakula et al., Macromol. Theory Simul., 5, 987-1006 (1996);-   A. Aksimetiev et al., J. of Chem. Physics, 111, No. 5;-   M. Janco, J. Polym. Sci., Part A: Polym. Chem. (2000), 38(15),    2767-2778;-   M. Zaremski et al., Macromolecules (2000), 33(12), 4365-4372;-   K. Matyjaszewski et al., J. Phys. Org. Chem. (2000), 13(12),    775-786;-   Gray, Polym. Prepr. (Am. Chem. Soc., Div. Polym. Chem.) (2001),    42(2), 337-338;-   K. Matyjaszewski, Chem. Rev. (Washington, D.C.) (2001), 101(9),    2921-2990.

Among gradient copolymers, it is possible to distinguish naturalgradient copolymers and artificial gradient copolymers.

A natural gradient copolymer is a gradient copolymer synthesized as abatch from a starting mixture of the comonomers. The distribution in thechain of the various monomers follows a law deduced from the relativereactivity and from the starting concentrations of monomers. Thesecopolymers constitute the simplest class of gradient copolymers as it isthe starting mixture which defines the final product property.

An artificial gradient copolymer is a copolymer for which theconcentration of monomers during the synthesis is varied by a processingexpedient. In this case, a mixture of monomers is changed to another inthe chain due to a sudden and abrupt change in the monomers in thereaction medium (stripping of the first mixture or addition of at leastone new monomer). It is even possible for one or more of the monomerstherein to completely disappear, to the advantage of one or more others.

The gradient can be characterized experimentally by measuring, duringpolymerization, the chemical composition of the polymer. Thismeasurement is performed indirectly by determining the change in thecontent of the various monomers at any instant. It can be performed byNMR and UV spectroscopy, for example. This is because, for the polymersprepared by living or pseudo-living polymerization, the length of thechains is linearly related to the conversion. By withdrawing a sample ofthe polymerization solution at various instants in the polymerizationand by measuring the difference in content of each monomer, thecomposition of the gradient is thus determined.

The distribution of the compositions of the chains is preferably narrowin the gradient polymer. In particular, there exists no overlap betweenthe peak of the gradient copolymer and those of the respectivehomopolymers. This means that the material obtained under gradientconditions is composed of polymer chains with the same compositionwhereas, in conventional random polymerization, different kinds of chaincoexist, including those of the respective homopolymers.

It is possible to characterize gradient copolymers by a vectorcharacteristic of each copolymer. This is because, knowing that thereexists an infinity of polymers characterized by a given chemicalcomposition, to specify a polymer it is possible to describe thedistribution of monomers along the chain. This involves a descriptioncomprising several variables. This vector is a point of the space of thechemical compositions. The exact term is that G is a vector, thecoordinates of which are the concentrations of the monomers along thepolymer chain. These concentrations are defined by the rules of thereactivity coefficients of each of the monomers and therefore arerelated to the concentration of the free monomers during the synthesis:from the moment that the monomer is not in zero concentration in thereaction mixture, it is not in zero concentration in the polymer.

It is therefore possible to characterize gradient copolymers by thefunction G(x) which defines the composition gradient:

{right arrow over (G)}(x)=Σ{right arrow over ([Mi](x))}

in which:

-   -   x denotes a normalized position on the polymer chain and    -   [Mi](x) is the relative concentration, in this position x, of        the monomer Mi, expressed in mol %.

The function G(x) therefore locally describes the composition of thegradient copolymer.

Two copolymers can have an equivalent composition overall but verydifferent local distributions of the monomers and therefore differentgradients.

For example, in the case of a (50/50) AB diblock, the function [A] has avalue of 1 up to x=½, and then 0 subsequently.

The factors which determine the gradient are, first, the relativereactivity coefficients of each monomer (referred to as r_(i) for themonomer Mi), which depend mainly on the type of synthesis processemployed (homogeneous, dispersed) and on the solvents, and, secondly,the starting concentrations of each of the monomers and the possibleadditions of monomers during the polymerization.

The gradient copolymer according to the invention comprises at least twodifferent monomers which are both chosen from isobornyl acrylate,isobornyl methacrylate, isobutyl acrylate, isobutyl methacrylate and2-ethylhexyl acrylate. In the continuation of the present description,these five monomers will be referred to as “selected monomers”.

The copolymer according to the invention can thus comprise from 1 to 99%by weight, with respect to the weight of the final copolymer, inparticular from 2 to 98% by weight, preferably from 5 to 95% by weight,indeed even from 30 to 70% by weight, of a first monomer chosen from the“selected monomers” and from 1 to 99% by weight, with respect to theweight of the final copolymer, in particular from 2 to 98% by weight,preferably from 5 to 95% by weight, indeed even from 30 to 70% byweight, of a second monomer, different from said first monomer, chosenfrom the “selected monomers”.

The copolymer according to the invention can also optionally comprisefrom 1 to 50% by weight, in particular from 5 to 40% by weight, indeedeven from 10 to 35% by weight, with respect to the weight of the finalcopolymer, of a third monomer, different from the first and secondmonomers, chosen from the “selected monomers”.

The total amount of monomers chosen from the selected monomers in thefinal copolymer is preferably between 50 and 100% by weight inclusive,in particular from 60 to 98% by weight, indeed even from 70 to 97% byweight, better still from 80 to 96% by weight, preferably from 90 to 95%by weight, with respect to the weight of the final copolymer.

Preference is very particularly given to the copolymers comprising:

-   -   isobornyl acrylate and isobornyl methacrylate;    -   isobornyl acrylate and isobutyl acrylate;    -   isobornyl acrylate and isobutyl methacrylate;    -   isobornyl acrylate and 2-ethylhexyl acrylate;    -   isobornyl methacrylate and isobutyl acrylate;    -   isobornyl methacrylate and isobutyl methacrylate;    -   isobornyl methacrylate and 2-ethylhexyl acrylate;    -   isobornyl acrylate, isobornyl methacrylate and 2-ethylhexyl        acrylate;    -   isobornyl acrylate, isobornyl methacrylate and isobutyl        acrylate;    -   isobornyl acrylate, isobutyl methacrylate and 2-ethylhexyl        acrylate;    -   isobornyl acrylate, isobutyl methacrylate and isobutyl acrylate;        or    -   isobornyl methacrylate, isobutyl methacrylate and isobutyl        acrylate.

The copolymer according to the invention can furthermore comprise atleast one additional monomer other than those chosen from the selectedmonomers.

This additional monomer or mixture of additional monomers can be presentin an amount of 0 to 50% by weight, in particular of 2 to 40% by weight,indeed even of 3 to 30% by weight, better still of 4 to 20% by weight,preferably of 5 to 10% by weight, with respect to the weight of thefinal copolymer.

This or these additional monomers can be chosen, alone or as a mixture,from the following monomers and their salts, with the exception, ofcourse, of the selected monomers mentioned above:

-   -   (i) (meth)acrylates of formula CH₂═CHCOOR or CH₂═C(CH₃)COOR in        which R represents:    -   a linear or branched alkyl group comprising 1 to 30 carbon atoms        in which is(are) optionally inserted one or more heteroatoms        chosen from O, N, S and P and/or said alkyl group being able to        be optionally substituted by one or more substituents chosen        from —OH, halogen atoms (Cl, Br, I and F), —NR₄R₅ groups, where        R₄ and R₅, which are identical or different, represent hydrogen        or a linear or branched C₁ to C₆ alkyl group or a phenyl group;        and/or polyoxyalkylene groups, in particular polyoxyethylene        and/or polyoxy-propylene, said polyoxyalkylene group being        composed of the repetition of 5 to 30 oxyalkylene units;    -   a C₃ to C₁₂ cycloalkyl group, said cycloalkyl group being able        to comprise, in its chain, one or more heteroatoms chosen from        O, N, S and/or P and/or being able to be optionally substituted        by one or more substituents chosen from —OH and halogen atoms        (Cl, Br, I and F);    -   a C₄ to C₂₀ aryl group or a C₅ to C₃₀ aralkyl group (C₁ to C₈        alkyl group);        in particular, R can be a methyl, ethyl, propyl, isopropyl,        n-butyl, isobutyl, tert-butyl, hexyl, ethyl-hexyl, octyl,        lauryl, isooctyl, isodecyl, dodecyl, cyclohexyl,        t-butylcyclohexyl, stearyl, 2-ethyl-perfluorohexyl,        2-hydroxyethyl, 2-hydroxybutyl, 2-hydroxypropyl, methoxyethyl,        ethoxyethyl, methoxy-propyl, isobornyl, phenyl, 2-phenylethyl,        t-butyl-benzyl, benzyl, furfurylmethyl or        tetrahydrofurfuryl-methyl, methoxypolyoxyethylene (or        POE-methyl), POE-behenyl, trifluoroethyl, dimethylaminoethyl,        diethyl-aminoethyl or dimethylaminopropyl group,    -   (ii) (meth)acrylamides of formula CH₂═CHCONR₄R₅ or CH₂═C(CH₃)        CONR₄R₅        in which R₄ and R₅, which are identical or different, represent        a hydrogen atom or:        a) a linear or branched alkyl group comprising from 1 to 18        carbon atoms in which is(are) optionally inserted one or more        heteroatoms chosen from O, N, S and P; said alkyl group being        able in addition to be optionally substituted by one or more        substituents chosen from hydroxyl groups, halogen atoms (Cl, Br,        I and F) and Si(R₄R₅) groups, where R₄ and R₅, which are        identical or different, represent a C₁ to C₆ alkyl group or a        phenyl group;        and in particular a methyl, ethyl, propyl, isopropyl, n-butyl,        isobutyl, tert-butyl, hexyl, isohexyl, cyclohexyl, ethylhexyl,        octyl, isooctyl, decyl, isodecyl, cyclodecyl, dodecyl,        cyclododecyl, isononyl, lauryl, t-butylcyclohexyl, stearyl or        2-ethylperfluoro-hexyl group; or a C₁₋₄ hydroxyalkyl group, such        as 2-hydroxyethyl, 2-hydroxybutyl and 2-hydroxypropyl; or a        (C₁₋₄)alkoxy(C₁₋₄)alkyl group, such as methoxyethyl, ethoxyethyl        and methoxypropyl,        b) a C₃ to C₁₂ cycloalkyl group, such as the isobornyl group, or        a heterocycloalkyl group (alkyl of 1 to 4 carbon atoms), such as        furfurylmethyl or tetrahydro-furfurylmethyl,        c) a C₄ to C₂₀ aryl group, such as the phenyl group,        d) a C₅ to C₃₀ aralkyl group (C₁ to C₈ alkyl group), such as        2-phenylethyl, t-butylbenzyl or benzyl,    -   (iii) monomers possessing ethylenic unsaturation(s) comprising        at least one carboxylic acid, phosphoric acid, sulfonic acid or        anhydride functional group, such as, for example, acrylic acid,        methacrylic acid, crotonic acid, maleic anhydride, itaconic        acid, fumaric acid, maleic acid, styrenesulfonic acid,        vinylbenzoic acid, vinylphosphoric acid,        acrylamidopropanesulfonic acid and the salts of these;    -   (iv) vinyl ethers of formula R₆O—CH═CH₂ or vinyl esters of        formula R₆—COO—CH═CH₂        in which R₆ represents a linear or branched alkyl group        comprising from 1 to 22 atoms or a cyclic alkyl group comprising        from 3 to 6 carbon atoms and/or an aromatic group, for example        of benzene, anthracene and naphthalene type;    -   (v) vinyl compounds of formula CH₂═CH—R₉, CH₂═CH—CH₂—R₉ or        CH₂═C(CH₃)—CH₂—R₉        in which R₉ is a hydroxyl group, a halogen group (Cl or F), an        NH₂ group, an OR₁₀ group, where R₁₀ represents a phenyl group or        a C₁ to C₁₂ alkyl group (the monomer is a vinyl or allyl ether),        an acetamide group (NHCOCH₃), an OCOR₁₁ group, where R₁₁        represents a linear or branched alkyl group of 2 to 12 carbons        (the monomer is a vinyl or allyl ester), or a group chosen from:    -   a linear or branched alkyl group of 1 to 18 carbon atoms in        which is(are) optionally inserted one or more heteroatoms chosen        from O, N, S and P, said alkyl group additionally being able to        be optionally substituted by one or more substituents chosen        from hydroxyl groups, halogen atoms (Cl, Br, I and F) and        Si(R₄R₅) groups, where R₄ and R₅, which are identical or        different, represent a C₁ to C₆ alkyl group or a phenyl group;    -   a C₃ to C₁₂ cycloalkyl group, such as isobornyl or cyclohexyl,    -   a C₃ to C₂₀ aryl group, such as phenyl,    -   a C₄ to C₃₀ aralkyl group (C₁ to C₈ alkyl group), such as        2-phenylethyl or benzyl,    -   a 4- to 12-membered heterocyclic group comprising one or more        heteroatoms chosen from O, N and S, the ring being aromatic or        nonaromatic,    -   a heterocycloalkyl group (alkyl of 1 to 4 carbon atoms), such as        furfurylmethyl or tetrahydrofur-furylmethyl,    -   (vi) styrene and its derivatives, in particular such as        methylstyrene, chlorostyrene or chloromethylstyrene;    -   (vii) monomers possessing ethylenic unsaturation comprising one        or more silicon atoms, such as        methacryloyloxypropyltrimethoxysilane or        methacryloyl-oxypropyltris(trimethylsiloxy)silane;    -   and their salts and their mixtures.

Mention may very particularly be made, among these additional monomers,of methyl (meth)acrylates, n-propyl (meth)acrylates, isopropyl(meth)acrylates, n-butyl (meth)acrylates, t-butyl (meth)acrylates,cyclohexyl (meth)acrylates, methoxyethyl (meth)acrylates, ethoxyethyl(meth)acrylates, trifluoroethyl (meth)acrylates, dimethylaminoethyl(meth)acrylates, diethylaminoethyl (meth)acrylates, 2-hydroxypropyl(meth)acrylates and 2-hydroxyethyl (meth)acrylates, acrylic acid,methacrylic acid, (meth)acrylamide,methacryloyloxypropyltrimethoxy-silane,methacryloyloxypropyltris(trimethylsiloxy)-silane, and their salts andtheir mixtures.

Use may also be made, as additional monomers, of carbon-based orsilicone macromonomers having at least one polymerizable end group. Themacromonomer is any polymer, in particular oligomer, comprising, on justone of its ends, an end group, in particular a polymerizable end group,capable of reacting during the polymerization reaction with the monomersunder consideration to form the side chains of the polymer; said endgroup can advantageously be a group possessing ethylenic unsaturationcapable of polymerizing by the radical route with the monomersconstituting the backbone. Said macromonomer makes it possible to formthe side chains of the copolymer. The polymerizable group of themacromonomer can advantageously be a group possessing ethylenicunsaturation capable of polymerizing by the radical route. Saidpolymerizable end group can in particular be a vinyl or (meth)acrylategroup. Mention may in particular be made, among the additionalmacromonomers capable of being employed, of, alone or as a mixture, andtheir salts:

(i) linear or branched C₈-C₂₂ alkyl (meth)acrylate homopolymers andcopolymers exhibiting a polymerizable end group chosen from vinyl or(meth)acrylate groups, among which may be mentioned poly(2-ethylhexylacrylate) macromonomers possessing a mono(meth)acrylate end;poly(dodecyl acrylate) or poly(dodecyl methacrylate) macromonomerspossessing a mono(meth)-acrylate end; poly(stearyl acrylate) orpoly(stearyl methacrylate) macromonomers possessing amono(meth)-acrylate end. Such macromonomers are disclosed in particularin patents EP 895 467 and EP 96 459.

-   -   (ii) polyolefins having an end group possessing ethylenic        unsaturation, in particular those having a (meth)acrylate end        group. Mention may in particular be made, as examples of such        polyolefins, of the following macromonomers, it being understood        that they have a (meth)acrylate end group: polyethylene        macromonomers, polypropylene macromonomers,        polyethylene/polypropylene copolymer macromonomers,        polyethylene/polybutylene copolymer macromonomers,        polyisobutylene macromonomers, polybutadiene macromonomers,        polyisoprene macromonomers, poly(ethylene/butylene)-polyisoprene        macromonomers. Such macromonomers are disclosed in particular in        U.S. Pat. No. 5,625,005, which mentions ethylene/butylene and        ethylene/propylene macromonomers possessing a reactive        (meth)acrylate end group. Mention may in particular be made of        poly(ethylene/butylene) methacrylate, such as that sold under        the name Kraton Liquid L-1253 by Kraton Polymers.    -   (iii) polydimethylsiloxanes possessing a mono(meth)-acrylate end        group, in particular those of following formula (IIa):

in which:

-   -   R₈ denotes a hydrogen atom or a methyl group, preferably methyl;    -   R₉ denotes a linear or branched, preferably linear, divalent        hydrocarbon group having from 1 to 10 carbon atoms and        optionally comprising one or two —O— ether bonds, preferably        ethylene, propylene or butylene;    -   R₁₀ denotes a linear or branched alkyl group having from 1 to 10        carbon atoms, in particular from 2 to 8 carbon atoms, preferably        methyl, ethyl, propyl, butyl or pentyl;    -   n denotes an integer ranging from 1 to 300, preferably ranging        from 3 to 200 and preferentially ranging from 5 to 100.

Mention may in particular be made, as silicone macro-monomers, ofmonomethacryloyloxypropylpolydimethyl-siloxanes, such as those soldunder the name PS560-K6 by UCT (United Chemical Technologies Inc.) orunder the name MCR-M17 by Gelest Inc.

Mention may be made, among the salts, of those obtained byneutralization of the acid groups using an inorganic base, such as LiOH,NaOH, KOH, Ca(OH)₂, NH₄OH or Zn(OH)₂, or with an organic base, such as aprimary, secondary or tertiary alkylamine, in particular triethylamineor butylamine. This primary, secondary or tertiary alkylamine cancomprise one or more nitrogen and/or oxygen atoms and can thus comprise,for example, one or more alcohol functional groups; mention may inparticular be made of 2-amino-2-methylpropanol, triethanolamine and2-(dimethylamino)propanol. Mention may also be made of lysine or3-(dimethylamino)propylamine.

Mention may also be made of salts of inorganic acids, such as sulfuricacid, hydrochloric acid, hydrobromic acid, hydriodic acid, phosphoricacid or boric acid. Mention may also be made of salts of organic acidswhich can comprise one or more carboxylic acid, sulfonic acid orphosphonic acid groups. These acids can be linear, branched or cyclicaliphatic acids or also aromatic acids. These acids can additionallycomprise one or more heteroatoms chosen from O and N, for example in theform of hydroxyl groups. Mention may in particular be made of propionicacid, acetic acid, terephthalic acid, citric acid and tartaric acid.

Preferably, the gradient copolymer according to the invention comprisesat least one monomer having a Tg of less than or equal to 20° C., inparticular of between −150° C. and 20° C., more particularly of between−130° C. and 18° C. and better still of between −120° C. and 15° C., ora mixture of such monomers.

These monomers can be chosen from the “selected monomers” mentionedabove and/or from the additional monomers.

This or these monomers with a Tg≦20° C. can be present in a proportionof 1 to 99% by weight, in particular 10 to 90% by weight, better still20 to 80% by weight, indeed even 25 to 75% by weight, with respect tothe total weight of the copolymer.

Preferably, the copolymer according to the invention thus also comprisesat least one monomer having a Tg of greater than or equal to 20° C., inparticular of between 25 and 150° C., more particularly of between 30and 145° C. and better still of between 40 and 140° C., or a mixture ofsuch monomers.

This or these monomers can be chosen from the “selected monomers”mentioned above and/or from the additional monomers.

The monomer or monomers with a Tg≧20° C. can thus be present in aproportion of 1 to 99% by weight, in particular 10 to 90% by weight,better still 20 to 80% by weight, indeed even 25 to 75% by weight, withrespect to the total weight of the copolymer.

By way of information, it should be noted that isobornyl acrylate has aTg of 94° C., isobornyl methacrylate has a Tg of 110° C. and isobutylmethacrylate has a Tg of 53° C., and are thus said to be of high Tg, ofgreater than 20° C., whereas isobutyl acrylate has a Tg of −24° C. and2-ethylhexyl acrylate has a Tg of −50° C., and are thus said to be oflow Tg, of less than 20° C.

In the present description, the term “monomer with a Tg” will denote themonomers for which the homopolymer has such a Tg. In the presentinvention, the Tg (or glass transition temperature) values aretheoretical Tg values determined from the theoretical Tg values of theconstitutive monomers of each of the blocks, which can be found in areference manual, such as the Polymer Handbook, 3rd ed., 1989, JohnWiley, according to the following relationship, referred to as the “Foxlaw”:

$\frac{1}{Tg} = {\sum\limits_{i}\left( \frac{\omega \; i}{Tgi} \right)}$

wi being the fraction by weight of the monomer i in the block underconsideration and Tgi being the glass transition temperature of thehomopolymer of the monomer i (in degrees Kelvin).

A person skilled in the art will know to choose the monomers and theiramounts according to the result desired, basing himself on his generalknowledge, in particular on the relative reactivity of each monomer. Inparticular, he will choose the monomers and their amounts, and thesolvent medium, so as to obtain a copolymer which is preferably solublein said solvent medium.

The gradient copolymers of the invention can be prepared by a personskilled in the art according to the following procedure:

1) A mixture of the various monomers is prepared, optionally in asolvent, preferably in a stirred reactor. A radical polymerizationinitiator and an agent for controlling the polymerization are added. Themixture is preferably placed under a gas atmosphere which is inert withrespect to radical polymerization, such as nitrogen or argon.

The choice may be made, as optional polymerization solvent, of thesolvent medium of the composition, which can thus comprise cosmeticsolvents and/or oils such as defined below. In particular, thepolymerization solvent can be chosen from alkyl acetates, such as butylacetate or ethyl acetate, aromatic solvents, such as toluene, oralkanes, such as isododecane, heptane or isohexadecane.

2) The mixture is brought with stirring to the desired polymerizationtemperature. This temperature is preferably chosen within a range from10° C. to 160° C., preferably from 25° C. to 130° C.

The choice of the polymerization temperature is preferably optimizedaccording to the chemical composition of the mixture of monomers. Thus,monomers having very high propagation kinetic constants and a weakeraffinity for the control agent will preferably be polymerized at lowtemperature.

3) The polymerization medium is optionally modified during thepolymerization, before 90% conversion of the starting monomers isachieved, by further addition of one or more monomers, in particular ofthe starting mixture. This addition can be carried out in various ways,which can range from the sudden addition all at once to the continuousaddition over the entire duration of the polymerization.4) The polymerization is halted when the desired degree of conversion isachieved. The overall composition of the copolymer depends on thisconversion. The polymerization is preferably halted after havingachieved at least 50% conversion, in particular at least 60%, preferablyafter having achieved at least 90% conversion.5) The possible residual monomers can be removed by any known method,such as by evaporation or by addition of an amount of conventionalpolymerization initiator, such as peroxide or azo derivatives.

It is also possible to carry out a semicontinuous polymerization, forexample by introducing all or part of the optional solvent, a portion ofthe monomers, in particular 1 to 20% by weight of the total weight ofmonomers, and a portion of the initiator, in particular 1 to 20% byweight of the total weight of initiator, into a reactor and by thenheating to the required temperature. The remainder of the solvent, ofthe monomers and of the initiator can be introduced by running in duringpolymerization. They can be introduced by running in separately oridentically.

The agent for controlling the polymerization can be (i) a nitroxide oran alkoxyamine; (ii) an organo-metallic complex in the presence of ahalogenated compound; or (iii) sulfur derivatives of xanthate,dithioester, trithiocarbonate or carbamate type.

The radical polymerization initiator can be chosen from any conventionalpolymerization initiator, such as compounds of azo type, and inparticular azobisiso-butyronitrile, or of peroxide type, such as organicperoxides having 6 to 30 carbon atoms, in particular benzoyl peroxide.

The radical polymerization initiator can also be an alkoxyamine whichcan advantageously be chosen to initiate the polymerization and, at thesame time, to release the nitroxide controlling this polymerization.

The polymerization initiator can be a halogenated organic compound, inparticular a halogenated alkyl or ester, such as ethyl2-bromoisobutyrate.

A person skilled in the art will know to choose the polymerizationinitiator according to the controlled radical polymerization techniqueenvisaged and/or according to the requirements of the application. Thus,a monofunctional initiator will result in asymmetric chains, whereas apolyfunctional initiator will result in macromolecules having a symmetrystarting from a core.

The copolymers according to the invention are very particularly solublein lipophilic solvent media, such as the solvents, in particularlipophilic solvents, and/or carbon-based oils conventionally employed incosmetics.

It should be remembered that the term “soluble” is understood to meanthat the polymer does not form a precipitate in the solvent.Advantageously, the copolymer according to the invention is soluble at aconcentration of at least 1% by weight in isododecane at 25° C., 1 atm.,preferably at a concentration of at least 5% by weight, indeed even ofat least 10% by weight.

The gradient copolymers according to the invention can be present in thetopical cosmetic or dermatological compositions in an amount of 0.1 to95% by weight, preferably 0.5 to 90% by weight, in particular 1 to 80%by weight, indeed even 5 to 70% by weight, with respect to the totalweight of the composition.

The copolymers can thus be present in the composition in the dissolvedform, for example dissolved in a cosmetic organic solvent or a cosmeticcarbon-based oil.

It has been found that the gradient copolymers according to theinvention are very particularly soluble and that they can additionallybe dissolved in large amounts without influencing the viscosity of thesolution.

The cosmetic or dermatological compositions according to the inventioncomprise, in addition to said copolymers, a physiologically acceptablemedium, in particular a cosmetically or dermatologically acceptablemedium, that is to say a medium compatible with keratinous substances,such as the skin of the face or body, the lips, the hair, the eyelashes,the eyebrows and the nails.

The composition can advantageously comprise a solvent medium which canbe a fatty phase which can itself comprise oils and/or solvents,preferably lipophilic solvents, and fatty substances which are solid atambient temperature, such as waxes, pasty fatty substances, gums andtheir mixtures.

Mention may preferably be made, among the constituents of the fattyphase, of the oils and/or solvents having an overall solubilityparameter according to the Hansen solubility space of less than or equalto 20 (MPa)^(1/2), preferably of less than or equal to 18 (MPa)^(1/2),better still of less than or equal to 17 (MPa)^(1/2).

The overall solubility parameter δ according to the Hansen solubilityspace is defined in the article “Solubility Parameter Values” by Eric A.Grulke in the work “Polymer Handbook”, 3rd edition, Chapter VII, pp.519-559, by the relationship:

δ=(dD ² +dP ² +dH ²)^(1/2)

in which

-   -   dD characterizes the London dispersion forces resulting from the        formation of dipoles induced during molecular impacts,    -   dP characterizes the forces of Debye interactions between        permanent dipoles, and    -   dH characterizes the forces of specific interactions (hydrogen        bond, acid/base or donor/acceptor type, and the like).

The definition of the solvents in the solubility space according toHansen is described in the paper by C. M. Hansen, “The Three-DimensionalSolubility Parameters”, J. Paint Technol., 39, 105 (1967).

Mention may be made, among the oils and/or solvents having an overallsolubility parameter according to the Hansen solubility space of lessthan or equal to 20 (MPa)^(1/2), of volatile or nonvolatile oils whichcan be chosen from optionally branched, carbon-based, hydrocarbon orfluorinated, natural or synthetic oils, alone or as a mixture; ethersand esters having more than 6 carbon atoms, in particular 6 to 30 carbonatoms; ketones having more than 6 carbon atoms, in particular 6 to 30carbon atoms; aliphatic fatty monoalcohols having 6 to 30 carbon atoms,the hydro-carbon chain not comprising a substituent group.

The term “nonvolatile oil” is understood to mean an oil capable ofremaining on the skin at ambient temperature and atmospheric pressurefor at least one hour and having in particular a nonzero vapor pressureat ambient temperature (25° C.) and atmospheric pressure of less than0.01 mmHg (1.33 Pa).

Mention may in particular be made of nonvolatile carbon-based oils, inparticular hydrocarbon oils, of vegetable, mineral, animal or syntheticorigin, such as liquid paraffin (or liquid petrolatum), squalane,hydrogenated polyisobutylene (Parleam oil), perhydrosqualene, mink oil,macadamia nut oil, turtle oil, soybean oil, sweet almond oil,calophyllum oil, palm oil, grape seed oil, sesame oil, corn oil, araraoil, rapeseed oil, sunflower oil, cottonseed oil, apricot oil, castoroil, avocado oil, jojoba oil, olive oil, cereal germ oil or shea butter;linear, branched or cyclic esters having more than 6 carbon atoms, inparticular 6 to 30 carbon atoms, such as esters of lanolic acid, ofoleic acid, of lauric acid or of stearic acid; esters derived fromlong-chain acids or alcohols (that is to say, having from 6 to 20 carbonatoms), in particular esters of formula RCOOR′ in which R represents theresidue of a higher fatty acid comprising from 7 to 19 carbon atoms andR′ represents a hydrocarbon chain comprising from 3 to 20 carbon atoms,in particular C₁₂-C₃₆ esters, such as isopropyl myristate, isopropylpalmitate, butyl stearate, hexyl laurate, diisopropyl adipate, isononylisononanoate, 2-ethylhexyl palmitate, 2-hexyldecyl laurate,2-octyl-decyl palmitate, 2-octyldodecyl myristate or lactate,di(2-ethylhexyl) succinate, diisostearyl malate, glyceryl triisostearateor diglyceryl triisostearate; higher fatty acids, in particular C₁₄-C₂₂fatty acids, such as myristic acid, palmitic acid, stearic acid, behenicacid, oleic acid, linoleic acid, linolenic acid or isostearic acid;higher fatty alcohols, in particular C₁₆-C₂₂ fatty alcohols, such asketanol, oleyl alcohol, linoleyl alcohol, linolenyl alcohol, isostearylalcohol, or octyldodecanol; and their mixtures.

Mention may also be made of decanol, dodecanol, octa-decanol, liquidtriglycerides of fatty acids of 4 to 10 carbon atoms, such astriglycerides of heptanoic or octanoic acids or triglycerides ofcaprylic/capric acids; linear or branched hydrocarbons of mineral orsynthetic origin, such as liquid paraffins and their derivatives, liquidpetrolatum, polydecenes, hydrogenated polyisobutene, such as Parleam;synthetic esters and ethers, in particular of fatty acids, such as, forexample, Purcellin oil, isopropyl myristate, 2-ethylhexyl palmitate,2-octyldodecyl stearate, 2-octyldodecyl erucate or isostearylisostearate; hydroxylated esters, such as isostearyl lactate, octylhydroxystearate, octyldodecyl hydroxystearate, diiso-stearyl malate,triisocetyl citrate, heptanoates, octanoates, decanoates of fattyalcohols; polyol esters, such as propylene glycol dioctanoate, neopentylglycol diheptanoate or diethylene glycol diiso-nonanoate;pentaerythritol esters; fatty alcohols having from 12 to 26 carbonatoms, such as octyl-dodecanol, 2-butyloctanol, 2-hexyldecanol or2-undecylpentadecanol.

Mention may also be made of ketones which are liquid at ambienttemperature, such as methyl ethyl ketone, methyl isobutyl ketone,diisobutyl ketone, isophorone, cyclohexanone or acetone; propyleneglycol ethers which are liquid at ambient temperature, such as propyleneglycol monomethyl ether, propylene glycol monomethyl ether acetate ordipropylene glycol mono(n-butyl)ether; short-chain esters (having atotal of 3 to 8 carbon atoms), such as ethyl acetate, methyl acetate,propyl acetate, n-butyl acetate or isopentyl acetate; ethers which areliquid at ambient temperature, such as diethyl ether, dimethyl ether ordichlorodiethyl ether; alkanes which are liquid at ambient temperature,such as decane, heptane, dodecane, isododecane, isohexa-decane orcyclohexane; aromatic cyclic compounds which are liquid at ambienttemperature, such as toluene and xylene; aldehydes which are liquid atambient temperature, such as benzaldehyde or acetaldehyde, and theirmixtures.

Mention may be made, among volatile compounds, of volatile non-siliconeoils, in particular C₈-C₁₆ isoparaffins, such as isododecane, isodecane,isohexa-decane and, for example, the oils sold under the Isopar andPermethyl trade names, in particular isododecane (Permethyl 99A).

More preferably, mention may be made of volatile or nonvolatile alkaneswhich are liquid at ambient temperature and more particularly decane,heptane, dodecane, isododecane, isohexadecane, cyclohexane, isodecaneand their mixtures.

These oils and/or solvents can generally be present in a content rangingfrom 0.01 to 95%, preferably from 0.1 to 90%, more preferably from 10 to85% by weight, with respect to the total weight of the composition, andbetter still from 30 to 80%.

The composition can additionally comprise a hydrophilic mediumcomprising water or a mixture of water and of hydrophilic organicsolvent(s), such as alcohols and in particular linear or branched lowermonoalcohols having from 2 to 5 carbon atoms, such as ethanol,isopropanol or n-propanol, and polyols, such as glycerol, diglycerol,propylene glycol, sorbitol, pentylene glycol and polyethylene glycols,or else hydrophilic C₂ ethers and hydrophilic C₂-C₄ aldehydes.

The water or the mixture of water and of hydrophilic organic solventscan be present in the composition according to the invention in acontent ranging from 0.1 to 80% by weight, with respect to the totalweight of the composition, and preferably from 1 to 70% by weight.

The composition according to the invention can also comprise waxesand/or gums.

The term “wax” is understood to mean, within the meaning of the presentinvention, a lipophilic compound which is solid at ambient temperature(25° C.), which has a reversible solid/liquid change in state and whichhas a melting point of greater than or equal to 30° C. which can rangeup to 120° C. On bringing the wax to the liquid state (melting), it ispossible to render it miscible with the oils which may be present and toform a microscopically homogeneous mixture but, on bringing thetemperature of the mixture back to ambient temperature,recrystallization of the wax in the oils of the mixture is obtained. Themelting point of the wax can be measured using a differential scanningcalorimeter (DSC), for example the calorimeter sold under the name DSC30 by Metler.

The waxes can be hydrocarbon, fluorinated and/or silicone waxes and canbe of vegetable, mineral, animal and/or synthetic origin. In particular,the waxes exhibit a melting point of greater than 25° C. and betterstill of greater than 45° C. Mention may be made, as waxes which can beused in the composition of the invention, of beeswax, carnauba wax,candelilla wax, paraffin wax, microcrystalline waxes, ceresin orozokerite; synthetic waxes, such as polyethylene or Fischer-Tropschwaxes, silicone waxes, such as alkyl or alkoxy dimethicones having from16 to 45 carbon atoms. The gums are generally polydimethylsiloxanes(PDMS) of high molecular weight or cellulose gums or polysaccharides andthe pasty substances are generally hydrocarbon compounds, such aslanolins and their derivatives or also PDMSs.

The nature and the amount of the solid substances depend on themechanical properties and textures desired. By way of indication, thecomposition can comprise from 0.01 to 50% by weight of waxes, withrespect to the total weight of the composition, and better still from 1to 30% by weight.

The composition according to the invention can additionally comprise oneor more coloring materials chosen from water-soluble dyes, fat-solubledyes and pulverulent coloring materials, such as pigments, pearlescentagents and glitters well known to a person skilled in the art. Thecoloring materials can be present in the composition in a contentranging from 0.01 to 50% by weight, with respect to the weight of thecomposition, preferably from 0.01 to 30% by weight. The term “pigments”should be understood as meaning white or colored and inorganic ororganic particles of any shape which are insoluble in the physiologicalmedium and which are intended to color the composition. The term“pearlescent agents” should be understood as meaning iridescentparticles of any shape, in particular produced by certain mollusks intheir shells or else synthesized. The pigments can be white or coloredand inorganic and/or organic. Mention may be made, among inorganicpigments, of titanium dioxide, optionally surface treated, zirconium orcerium oxides, zinc, iron or chromium oxides (the iron oxides beingblack, yellow or red), manganese violet, ultramarine blue, chromiumhydrate, ferric blue or metal powders, such as aluminum powder or copperpowder. Mention may be made, among organic pigments, of carbon black,pigments of D & C type, and lakes based on cochineal carmine of barium,strontium, calcium or aluminum. The pearlescent pigments can be chosenfrom white pearlescent pigments, such as mica covered with titaniumoxide or with bismuth oxychloride, colored pearlescent pigments, such astitanium oxide-coated mica covered with iron oxides, titaniumoxide-coated mica covered with in particular ferric blue or withchromium oxide, or titanium oxide-coated mica covered with an organicpigment of the abovementioned type, and pearlescent pigments based onbismuth oxychloride. Mention may be made, among water-soluble dyes, ofthe disodium salt of ponceau, the disodium salt of alizarin green,quinoline yellow, the trisodium salt of amaranth, the disodium salt oftartrazine, the monosodium salt of rhodamine, the disodium salt offuchsin, xanthophyll or methylene blue.

The composition according to the invention can additionally comprise oneor more fillers, in particular in a content ranging from 0.01% to 50% byweight, with respect to the total weight of the composition, preferablyranging from 0.01% to 30% by weight. The term “fillers” should beunderstood as meaning colorless or white and inorganic or syntheticparticles of any shape which are insoluble in the medium of thecomposition, whatever the temperature at which the composition ismanufactured. These fillers are used in particular to modify therheology or the texture of the composition. The fillers can be inorganicor organic and of any shape, platelet, spherical or oblong, whatever thecrystallographic form (for example sheet, cubic, hexagonal,orthorhombic, and the like). Mention may be made of talc, mica, silica,kaolin, polyamide (Nylon®) powders (Orgasol® from Atochem),poly-β-alanine powders, polyethylene powders, powders formed oftetrafluoroethylene polymers (Teflon®), lauroyllysine, starch, boronnitride, polymeric hollow microspheres, such as those ofpolyvinylidene/acrylonitrile chloride, for example Expancel® (NobelIndustrie), or of acrylic acid copolymers (Polytrap® from Dow Corning),silicone resin microbeads (Tospearls® from Toshiba, for example),polyorganosiloxane elastomer particles, precipitated calcium carbonate,magnesium carbonate, basic magnesium carbonate, hydroxyapatite, hollowsilica microspheres (Silica Beads® from Maprecos), glass or ceramicmicrocapsules, or metal soaps derived from organic carboxylic acidshaving from 8 to 22 carbon atoms, preferably from 12 to 18 carbon atoms,for example zinc stearate, magnesium stearate, lithium stearate, zinclaurate or magnesium myristate.

The composition can furthermore comprise an additional polymer, such asa film-forming polymer. According to the present invention, the term“film-forming polymer” is understood to mean a polymer capable offorming, by itself alone or in the presence of an additional agent whichis able to form a film, a continuous film which adheres to a support, inparticular to keratinous substances. Mention may be made, among thefilm-forming polymers capable of being used in the composition of thepresent invention, of synthetic polymers of radical type or ofpolycondensate type, polymers of natural origin and their mixtures, inparticular acrylic polymers, polyurethanes, polyesters, polyamides,polyureas or cellulose polymers, such as nitrocellulose.

The composition according to the invention can also comprise ingredientscommonly used in cosmetics, such as vitamins, thickeners, gellingagents, trace elements, softening agents, sequestering agents,fragrances, basifying or acidifying agents, preservatives, sunscreens,surfactants, antioxidants, agents for combating hair loss, antidandruffagents, propellants, ceramides or their mixtures. Of course, a personskilled in the art will take care to choose this or these optionaladditional compounds and/or their amounts so that the advantageousproperties of the composition according to the invention are not, or notsubstantially, detrimentally affected by the envisaged condition.

The composition according to the invention can be provided in particularin the form of a suspension, a dispersion, a solution, in particularorganic, a gel, an emulsion, in particular oil-in-water (O/W) orwater-in-oil (W/O) or multiple (W/O/W or polyol/O/W or O/W/O) emulsion,a cream, a foam, a dispersion of vesicles, in particular of ionic ornonionic lipids, a two-phase or multiphase lotion, a spray, a powder, apaste, in particular a soft paste (in particular a paste having adynamic viscosity at 25° C. of the order of 0.1 to 40 Pa·s under a shearrate of 200 s⁻¹, after measuring for 10 minutes by cone/plate geometry).The composition can be anhydrous; for example, it can be an anhydrouspaste.

A person skilled in the art can choose the appropriate formulation formand its method of preparation on the basis of his general knowledge,taking into account, on the one hand, the nature of the constituentsused, in particular their solubility in the support, and, on the otherhand, the application envisaged for the composition.

The composition according to the invention can be a makeup composition,in particular a product for the complexion, such as a foundation, a facepowder or an eyeshadow; a product for the lips, such as a lipstick or alip care product; a concealer; a blusher, a mascara or an eyeliner; aproduct for making up the eyebrows, a lip pencil or an eye pencil; aproduct for the nails, such as a nail varnish or a nail care product; aproduct for making up the body; a product for making up the hair (hairmascara or lacquer).

The composition according to the invention can be a composition forprotecting or caring for the skin of the face, of the neck, of the handsor of the body, in particular a composition for combating wrinkles orfatigue which makes it possible to give radiance to the skin, amoisturizing or treating composition; an antisun or artificial tanningcomposition.

The composition according to the invention can also be a hair product,in particular for the form retention of the hairstyle or the shaping ofthe hair. The hair compositions are preferably shampoos, gels,hairsetting lotions, blow drying lotions or fixing and stylingcompositions, such as lacquers or sprays. The lotions can be packaged invarious forms, in particular in vaporizers, pump-action sprays oraerosol containers, in order to provide for application of thecomposition in the vaporized form or in the foam form. Such packagingforms are indicated, for example, when it is desired to obtain a sprayor a foam for the fixing or the treatment of the hair.

Advantageously, the composition according to the invention can be amakeup composition, in particular a foundation or a lipstick.

Another subject matter of the invention is a cosmetic process for makingup or caring for keratinous substances, in particular the skin of thebody or face, the nails, the hair and/or the eyelashes, comprising theapplication, to said substances, of a cosmetic composition as definedabove.

In particular, a subject matter of the invention is a cosmetic processfor making up the skin of the face and/or the lips, comprising theapplication, to said substances, of a foundation or lipstick cosmeticcomposition as defined above.

EXAMPLE 1

3.5 g of isobornyl acrylate (1.7×10⁻² mol), 3.5 g of isobornylmethacrylate (1.6×10⁻² mol), 3 g of isobutyl acrylate (2.3×10⁻² mol) and10 g of butyl acetate are mixed in a 100 ml three-necked flask equippedwith a reflux condenser and placed under an argon flow.

This mixture is degassed by bubbling with argon for 15 minutes and then40 mg of CuBr, 49 mg of PMDETA(N,N,N′,N′,N″-pentamethyldiethylenetriamine) and 55.6 mg of ethyl2-bromoisobutyrate are added. The reaction mixture is brought to 100° C.for 2 hours and then filtered through alumina.

A solution of the polymer in butyl acetate (50% of dry matter DM) isobtained.

The butyl acetate can be distilled off and can be substituted byisododecane (10 g). A solution of the polymer in isododecane (50% DM) isthen obtained.

EXAMPLE 2

3.5 g of isobornyl acrylate, 3.5 g of isobornyl methacrylate, 3 g of2-ethylhexyl acrylate and 10 g of butyl acetate are mixed in a 100 mlthree-necked flask equipped with a reflux condenser and placed under anargon flow.

This mixture is degassed by bubbling with argon for 15 minutes and then40 mg of CuBr, 49 mg of PMDETA(N,N,N′,N′,N″-pentamethyldiethylenetriamine) and 55.6 mg of ethyl2-bromoisobutyrate are added. The reaction mixture is brought to 100° C.for 2 hours and then filtered through alumina.

A solution of the polymer in butyl acetate (50% of dry matter DM) isobtained.

The butyl acetate can be distilled off and can be substituted byisododecane (10 g). A solution of the polymer in isododecane (50% DM) isthen obtained.

EXAMPLE 3

5 g of isobornyl acrylate, 5 g of isobutyl acrylate and 10 g of butylacetate are mixed in a 100 ml three-necked flask equipped with a refluxcondenser and placed under an argon flow.

This mixture is degassed by bubbling with argon for 15 minutes and then40 mg of CuBr, 49 mg of PMDETA(N,N,N′,N′,N″-pentamethyldiethylenetriamine) and 55.6 mg of ethyl2-bromoisobutyrate are added. The reaction mixture is brought to 100° C.for 2 hours and then filtered through alumina.

A solution of the polymer in butyl acetate (50% of dry matter DM) isobtained.

The butyl acetate can be distilled off and can be substituted byisododecane (10 g). A solution of the polymer in isododecane (50% DM) isthen obtained.

EXAMPLE 4

A nail varnish is prepared which comprises:

-   -   40% by weight of solution of the polymer of example 1 in butyl        acetate with a DM of 50%    -   q.s. for 100% of organic solvents (butyl acetate and ethyl        acetate).

EXAMPLE 5

An anhydrous foundation is prepared which comprises (% by weight):

Polyethylene wax 12% Volatile silicone oils 25% Phenyl trimethicone 20%Poly (methyl methacrylate) microspheres 12% Solution of the polymer ofexample 2 in 12% isododecane with a DM of 50% (i.e., 6% of polymer drymatter) Isododecane q.s. for 100%

Preparation:

The waxes are melted and then, when all is clear, the phenyltrimethicone is added with stirring and the silicone oils are added;subsequently the microspheres, the isododecane and the polymer areadded. The mixture is homogenized for 15 minutes and then the resultingcomposition is cast and left to cool. An anhydrous foundation isobtained.

EXAMPLE 6

A lipstick stick is prepared which comprises:

Polyethylene wax 15% Solution of the polymer of example 3 in 20%isododecane with a DM of 50% (i.e., 10% of polymer dry matter)Hydrogenated polyisobutene (Parleam from 25% Nippon Oil Fats) Pigments10% Isododecane q.s. for 100%

The composition obtained exhibits good cosmetic properties afterapplication to the lips.

EXAMPLE 7

A foundation composition is prepared which comprises (% by weight):

Phase A

Cetyl dimethicone copolyol (Abil EM 90 from 3 g Goldschmidt) Isostearyldiglyceryl succinate (Imwitor 0.6 g 780K from Condea) Pigments (oxidesof iron and of titanium) 10 g Polyamide (Nylon 12) powder 8 g Solutionof the polymer of example 1 in 17 g isododecane with a DM of 50% (i.e.,8.5% of polymer dry matter) Fragrance q.s. Isododecane 10 g

Phase B

Magnesium sulfate 0.7 g Preservative q.s. Water q.s. for 100 g

The composition obtained exhibits good cosmetic properties.

1-33. (canceled)
 34. A gradient copolymer comprising at least twodifferent monomers chosen from isobornyl acrylate, isobornylmethacrylate, isobutyl acrylate, isobutyl methacrylate and 2-ethylhexylacrylate.
 35. The copolymer according to claim 34, wherein a firstmonomer chosen from isobornyl acrylate, isobornyl methacrylate, isobutylacrylate, isobutyl methacrylate and 2-ethylhexyl acrylate is present inan amount ranging from 1 to 99% by weight, relative to the weight of thefinal copolymer.
 36. The copolymer according to claim 35, wherein saidfirst monomer is present in an amount ranging from 30 to 70% by weight,relative to the weight of the final copolymer.
 37. The copolymeraccording to claim 35, wherein a second monomer chosen from isobornylacrylate, isobornyl methacrylate, isobutyl acrylate, isobutylmethacrylate and 2-ethylhexyl acrylate, but different from said firstmonomer, is present in an amount ranging from 1 to 99% by weight,relative to the weight of the final copolymer.
 38. The copolymeraccording to claim 37, wherein said second monomer is present in anamount ranging from 30 to 70% by weight, relative to the weight of thefinal copolymer.
 39. The copolymer according to claim 34, furthercomprising a third monomer, chosen from isobornyl acrylate, isobornylmethacrylate, isobutyl acrylate, isobutyl methacrylate and 2-ethylhexylacrylate, present in an amount ranging from 1 to 50% by weight, relativeto the weight of the final copolymer.
 40. The copolymer according toclaim 39, wherein said third monomer is present in an amount rangingfrom 10 to 35% by weight, relative to the weight of the final copolymer.41. The copolymer according to claim 34, wherein the total amount ofmonomers chosen from isobornyl acrylate, isobornyl methacrylate,isobutyl acrylate, isobutyl methacrylate and 2-ethylhexyl acrylate inthe final copolymer ranges from 50 to 100% by weight, relative to theweight of the final copolymer.
 42. The copolymer according to claim 41,wherein the total amount of monomers chosen from isobornyl acrylate,isobornyl methacrylate, isobutyl acrylate, isobutyl methacrylate and2-ethylhexyl acrylate in the final copolymer is present in an amountranging from 90 to 95% by weight, relative to the weight of the finalcopolymer.
 43. The copolymer according to claim 34, comprising at leastone of the following combinations of monomers: isobornyl acrylate andisobornyl methacrylate; isobornyl acrylate and isobutyl acrylate;isobornyl acrylate and isobutyl methacrylate; isobornyl acrylate and2-ethylhexyl acrylate; isobornyl methacrylate and isobutyl acrylate;isobornyl methacrylate and isobutyl methacrylate; isobornyl methacrylateand 2-ethylhexyl acrylate; isobornyl acrylate, isobornyl methacrylateand 2-ethylhexyl acrylate; isobornyl acrylate, isobornyl methacrylateand isobutyl acrylate; isobornyl acrylate, isobutyl methacrylate and2-ethylhexyl acrylate; isobornyl acrylate, isobutyl methacrylate andisobutyl acrylate; and isobornyl methacrylate, isobutyl methacrylate andisobutyl acrylate.
 44. The copolymer according to claim 34, furthercomprising at least one additional monomer, other than those chosen fromisobornyl acrylate, isobornyl methacrylate, isobutyl acrylate, isobutylmethacrylate and 2-ethylhexyl acrylate.
 45. The copolymer according toclaim 44, wherein the at least one additional monomer is present in anamount ranging from 0 to 50% by weight, relative to the weight of thefinal copolymer.
 46. The copolymer according to claim 45, wherein the atleast one additional monomer is present in an amount ranging from 5 to10% by weight, with respect to the weight of the final copolymer. 47.The copolymer according to claim 44, wherein the at least one additionalmonomer is chosen, alone or as a mixture, from: (i) (meth)acrylates offormula CH₂═CHCOOR or CH₂═C(CH₃)COOR wherein R is chosen from: a linearor branched alkyl group comprising 1 to 30 carbon atoms in which isoptionally inserted at least one heteroatom chosen from O, N, S and P,said alkyl groups being optionally substituted by at least onesubstituent chosen from —OH, halogen atoms chosen from Cl, Br, I, and F,—NR₄R₅ groups, wherein R₄ and R₅, which are identical or different, areeach independently chosen from hydrogen atoms, linear or branched C₁ toC₆ alkyl groups, phenyl groups; and polyoxyalkylene groups composed ofthe repetition of 5 to 30 oxyalkylene units; a C₃ to C₁₂ cycloalkylgroup, said cycloalkyl group optionally comprising, in its chain, atleast one heteroatom chosen from O, N, S and P and being optionallysubstituted by at least one substituent chosen from —OH and halogenatoms chosen from Cl, Br, I, and F; a C₄ to C₂₀ aryl group or a C₅ toC₃₀ aralkyl group wherein the alkyl portion is a C₁ to C₈ alkyl; (ii)(meth)acrylamides of formula CH₂═CHCONR₄R₅ or CH₂═C(CH₃) CONR₄R₅ whereinR₄ and R₅, which are identical or different, are each independentlychosen from hydrogen atoms and: a) linear or branched alkyl groupscomprising from 1 to 18 carbon atoms in which is optionally inserted atleast one heteroatom chosen from O, N, S and P; said alkyl group beingoptionally substituted by at least one substituent chosen from hydroxylgroups, halogen atoms chosen from Cl, Br, I, and F and Si(R₄R₅) groups,wherein R₄ and R₅, which are identical or different, are eachindependently chosen from C₁ to C₆ alkyl groups and phenyl groups; b) C₃to C₁₂ cycloalkyl groups, and heterocycloalkyl groups having an alkylportion of 1 to 4 carbon atoms, c) C₄ to C₂₀ aryl groups, d) C₅ to C₃₀aralkyl groups, wherein said alkyl portion has C₁ to C₈ alkyl groups,(iii) monomers possessing at least one ethylenic unsaturation comprisingat least one functional group chosen from carboxylic acids, phosphoricacids, sulfonic acids, and anhydrides, and the salts thereof; (iv) vinylethers of formula R₆O—CH═CH₂ and vinyl esters of formula R₆—COO—CH═CH₂wherein R₆ is chosen from a linear or branched alkyl group comprisingfrom 1 to 22 atoms, a cyclic alkyl group comprising from 3 to 6 carbonatoms, and an aromatic group; (v) vinyl compounds of formula CH₂═CH—R₉,CH₂═CH—CH₂—R₉ or CH₂═C(CH₃)—CH₂—R₉ wherein R₉ is chosen from a hydroxylgroup, a halogen group chosen from Cl and F, an NH₂ group, an OR₁₀group, wherein R₁₀ is chosen from a phenyl group and a C₁ to C₁₂ alkylgroup such that the monomer is a vinyl or allyl ether, an acetamidegroup (NHCOCH₃), an OCOR₁₁ group, wherein R₁₁ is a linear or branchedalkyl group of 2 to 12 carbons such that the monomer is a vinyl or allylester, and a group chosen from: a linear or branched alkyl group of 1 to18 carbon atoms in which is optionally inserted at least one heteroatomchosen from O, N, S and P, said alkyl group additionally beingoptionally substituted by at least one substituent chosen from hydroxylgroups, halogen atoms chosen from Cl, Br, I, and F and Si(R₄R₅) groups,wherein R₄ and R₅, which are identical or different, are eachindependently chosen from C₁ to C₆ alkyl groups and phenyl groups; a C₃to C₁₂ cycloalkyl group, a C₃ to C₂₀ aryl group, a C₄ to C₃₀ aralkylgroup (C₁ to C₈ alkyl groups), a 4- to 12-membered heterocyclic groupcomprising at least one heteroatom chosen from O, N and S, the ringbeing aromatic or nonaromatic, a heterocycloalkyl group wherein saidalkyl portion comprises 1 to 4 carbon atoms, (vi) styrene and itsderivatives; (vii) monomers possessing ethylenic unsaturation comprisingat least one silicon atom; and salts and mixtures thereof; with theproviso that the at least one additional monomer is not chosen fromisobornyl acrylate, isobornyl methacrylate, isobutyl acrylate, isobutylmethacrylate and 2-ethylhexyl acrylate.
 48. The copolymer according toclaim 44, wherein the at least one additional monomer is chosen frommethyl (meth)acrylates, n-propyl (meth)acrylates, isopropyl(meth)acrylates, n-butyl (meth)acrylates, t-butyl (meth)acrylates,cyclohexyl (meth)acrylates, methoxyethyl (meth)acrylates, ethoxyethyl(meth)acrylates, trifluoroethyl (meth)acrylates, dimethylaminoethyl(meth)acrylates, diethylaminoethyl (meth)acrylates, 2-hydroxypropyl(meth)acrylates, 2-hydroxyethyl (meth)acrylates, acrylic acid,methacrylic acid, (meth) acrylamide,methacryloyloxy-propyltrimethoxysilane, andmethacryloyloxypropyltris-(trimethylsiloxy)silane, and salts andmixtures thereof.
 49. The copolymer according to claim 44, wherein theat least one additional monomer is chosen, alone or as a mixture, fromcarbon-based or silicone macro-monomers having at least onepolymerizable end group and their salts.
 50. The copolymer according toclaim 49, wherein said carbon-based or silicone macro-monomers having atleast one polymerizable end group, and salts thereof, are chosen from(i) linear or branched C₈-C₂₂ alkyl (meth)acrylate homopolymers andcopolymers comprising a polymerizable end group chosen from vinyl and(meth)acrylate groups; (ii) polyolefins comprising an end group havingethylenic unsaturation; and (iii) polydimethylsiloxanes comprising amono(meth)-acrylate end group.
 51. The copolymer according to claim 34,comprising at least one monomer having a Tg of less than or equal to 20°C.
 52. The copolymer according to claim 51, comprising at least onemonomer having a Tg ranging from −120° C. to 15° C.
 53. The copolymeraccording to claim 51, wherein the at least one monomer with a Tg≦20° C.is present in an amount ranging from 1 to 99% by weight, relative to thetotal weight of the copolymer.
 54. The copolymer according to claim 53,wherein the at least one monomer with a Tg≦20° C. is present in anamount ranging from 25 to 75% by weight, relative to the total weight ofthe copolymer.
 55. The copolymer according to claim 34, comprising atleast one monomer having a Tg of greater than or equal to 20° C.
 56. Thecopolymer according to claim 55, comprising at least one monomer havinga Tg ranging from 40 to 140° C.
 57. The copolymer according to claim 55,wherein the at least one monomer with a Tg≧20° C. is present in anamount ranging from 1 to 99% by weight, relative to the total weight ofthe copolymer.
 58. The copolymer according to claim 57, wherein the atleast monomer with a Tg≧20° C. is present in an amount ranging from 25to 75% by weight, relative to the total weight of the copolymer.
 59. Thecopolymer according to claim 34, wherein the copolymer is soluble inisododecane at 25° C., 1 atm., at a concentration of at least 1% byweight.
 60. The copolymer according to claim 59, wherein the copolymeris soluble in isododecane at 25° C., 1 atm., at a concentration of atleast 10% by weight.
 61. The copolymer according to claim 34, whereinthe copolymer has a weight polydispersity index of less than or equal to3.
 62. The copolymer according to claim 61, wherein the copolymer has aweight polydispersity index ranging from 1.2 to 1.8.
 63. The copolymeraccording to claim 34, wherein the copolymer has, on a liquidchromatography curve, a difference V^(1/2) max-V^(1/2) min, wherein V iselution volume, of less than or equal to 3.5.
 64. The copolymeraccording to claim 63, wherein the copolymer has a difference V^(1/2)max-V^(1/2) min ranging from 1.1 to 2.0.
 65. A cosmetic ordermatological composition comprising, in a physiologically acceptablemedium, at least one gradient copolymer comprising at least twodifferent monomers chosen from isobornyl acrylate, isobornylmethacrylate, isobutyl acrylate, isobutyl methacrylate and 2-ethylhexylacrylate.
 66. The composition according to claim 65, wherein thecopolymer is present in an amount ranging from 0.1 to 95% by weight,relative to the total weight of the composition.
 67. The compositionaccording to claim 66, wherein the copolymer is present in an amountranging from 5 to 70% by weight, relative to the total weight of thecomposition.
 68. The composition according to claim 65, comprising atleast one fatty phase which comprises oils and/or solvents having anoverall solubility parameter according to the Hansen solubility space ofless than or equal to 20 (MPa)^(1/2).
 69. The composition according toclaim 65, comprising at least one oil and/or solvent chosen fromvolatile or nonvolatile oils which can be chosen from optionallybranched, carbon-based, hydrocarbon or fluorinated, natural or syntheticoils, alone or as a mixture; ethers and esters having more than 6 carbonatoms; ketones having more than 6 carbon atoms; aliphatic fattymonoalcohols having 6 to 30 carbon atoms, wherein the hydrocarbon chaindoes not comprise a substituent group.
 70. The composition according toclaim 65, wherein the at least one oil and/or solvent is chosen fromvolatile or nonvolatile alkanes chosen from decane, heptane, dodecane,isododecane, isohexa-decane, isodecane, cyclohexane, and mixturesthereof.
 71. The composition according to claim 65, comprising at leastfrom 0.01 to 95% by weight of at least one oil and/or solvent, relativeto the total weight of the composition.
 72. The composition according toclaim 71, comprising at least from 30 to 80% by weight of at least oneoil and/or solvent, relative to the total weight of the composition. 73.The composition according to claim 65, further comprising a constituentchosen from a hydrophilic medium comprising water or a mixture of waterand of hydrophilic organic solvent; waxes; gums; coloring materials;fillers; polymers; vitamins, thickeners, gelling agents, trace elements,softening agents, sequestering agents, fragrances, basifying oracidifying agents, preservatives, sunscreens, surfactants, antioxidants,agents for combating hair loss, antidandruff agents, propellants,ceramides and mixtures thereof.
 74. The composition according to claim65, wherein the composition is in a form chosen from a suspension, adispersion, a solution, a gel, an emulsion, a cream, a foam, adispersion of vesicles, a two-phase or multiphase lotion, a spray, apowder, a paste, and in the anhydrous form.
 75. The compositionaccording to claim 74, wherein the composition is in a form chosen froman organic solution; an oil-in-water (O/W), a water-in-oil (W/O), or amultiple (W/O/W or polyol/O/W or O/W/O) emulsion; a dispersion ofvesicles comprising ionic or nonionic lipids; a soft paste; and ananhydrous paste.
 76. The composition according to claim 65, wherein thecomposition is chosen from a makeup composition; a product for the lips;a concealer; a blusher, a mascara, an eyeliner; a product for making upthe eyebrows, a lip pencil, an eye pencil; a product for the nails; aproduct for making up the body; a product for making up the hair; acomposition for protecting or caring for the skin of the face, of theneck, of the hands or of the body; an antisun or artificial tanningcomposition; and a hair composition.
 77. The composition according toclaim 76, wherein the composition is chosen from a foundation, a facepowder, an eyeshadow, a lipstick, a lip care product, a nail varnish, anail care product, hair mascara, hair lacquer, a composition forcombating wrinkles or fatigue, a moisturizing composition, a treatingcomposition, and a hair composition for the form retention of thehairstyle or the shaping of the hair.
 78. The composition according toclaim 77, wherein the composition is in the form chosen from afoundation and a lipstick.
 79. A cosmetic process for making up orcaring for keratinous substances comprising the application, to saidsubstances, of a cosmetic composition comprising, in a physiologicallyacceptable medium, at least one gradient copolymer comprising at leasttwo different monomers chosen from isobornyl acrylate, isobornylmethacrylate, isobutyl acrylate, isobutyl methacrylate and 2-ethylhexylacrylate.
 80. A cosmetic process according to claim 79, wherein thekerantinous substances are chosen from the skin of the body or face, thenails, the hair and the eyelashes.
 81. A cosmetic process for making upthe skin of the face and/or lips, comprising the application, to saidsubstances, of a foundation or lipstick cosmetic composition comprising,in a physiologically acceptable medium, at least one gradient copolymercomprising at least two different monomers chosen from isobornylacrylate, isobornyl methacrylate, isobutyl acrylate, isobutylmethacrylate and 2-ethylhexyl acrylate.